The ideal fishing line would have very low elongation up to very close to its ultimate breaking load and just prior to breaking be able to absorb a very large amount of energy.
The most commonly used fishing lines of today are of either the braided or monofilament type. Braided fishing lines have been known for a long time and have been used particularly in casting because of flexibility which makes it easier to cast with more accurate results. The braided line also has the advantage of low stretch or elongation which permits the fisherman to set the hook more readily. However, there also are disadvantages to using braided line in that the braided line has a relatively short life due to abrading by contact with the reel, rod and objects either above or in the water.
To overcome some of the disadvantages of the earlier developed braided fishing line the monofilament fishing line was developed which is smaller diametrically for the same # test. In addition it has a smoother surface and therefore is less likely to abrade.
The monofilament line, however, has the disadvantageous property of greater elongation which makes the line less sensitive. This makes it more difficult for the fisherman to sense a strike or to set the hook.
However, neither of the fishing lines can answer one of the problems which every fisherman has, i.e., to know when his line is about to break from too great a tensile loading. The currently used lines whether braided or monofilament do not in any way indicate to the fisherman that he has too great a tensile loading and is about to have his line break if some remedial action is not taken. This too high tensile loading may be the result of the fisherman having too big a fish on his line for the # test being used or the drag setting of the reel is too high.